Hydraulic fluid mechanism



Nov. 20, 1951 J. w. OVERBEKE HYDRAULIC FLUID MECHANISM 2 SHEETS-SHEET 1Filed July 51, 1946 ATTORNEYS INVENTOR. JOHN- W. OVEEBEKE' ====rihl|llL==== Nov. 20, 1951 J w QVERBEKE 2,575,528

HYDRAULIC FLUID MECHANISM Filed July 31, 1946 v 2 SHEETSSHEET 2INVENTOR. 70 H/V W- OVEIEBEAE ATTOR EY;

Patented Nov. 20, 1951 UNITED STATES PATENT OFFICE HYDRAULIC FLUIDMECHANISM John W. Overbeke, Cleveland, Ohio Application July 31, 1946,Serial No. 687,399

7 Claims. (Cl. 103-161) This invention relates to fluid motors and pumpsof the positive displacement type, and more specifically to improvementsin mechanism for actuating the pistons therein. The invention isparticularly adapted for use in pumps of the type provided with arotating cylinder block having radial cylinders, and an eccentric ringthat guides the pistons in their reciprocating movement within thecylinders, although the princip ples of the invention may be employed inpumps of other types.

It has been common practice to provide radial cylinder pumps with astationary eccentric guiding ring circumambient the cylinder block andto provide arcuate shoes on the outer ends of the pistons for slidingengagement with the inner surface of the guiding ring. It has also beenproposed to mount the guide ring for free rotation within the pumpcasing and to effect the movement thereof with the cylinder block by thefrictional resistance between the piston shoes and the ring.

This invention is directed to the provision of a positive drive couplingbetween the cylinder block and the guide ring or track and to astructure which will eifect a rotary motion of the pistons within thecylinders in order to equalize the wear upon the cylindrical parts. Theinvention further contemplates the elimination of the piston shoes byvirtue of which the overall dimensions of the pump may be greatlyreduced, the frictional losses and wear minimized, and the operativeefliciency of the pump increased. In the type of construction embodyingpiston shoes engaged with a fixed track, the proportions of the pumpfrequently exceed the dimensional limitations of the mechanism withwhich the pump is associated; the restriction against rotation of thepistons increases the probability of cylinder scoring; and the weight ofreciprocating parts and inertia effects thereof increases the frictionlosses of the pump. Furthermore, this invention makes practicable theuse of a rigid rotating ring for receiving and distributing the pistonreaction forces, which ring may have a continuous bearing surface in thecasing which is easily lubricated.

While it would appear upon a cursory analysis that these problems couldbe solved by the provision of a freely rotatable track driven byfrictional engagement of the pistons with the track, experiment hasshown that this construction is unsatisfactory, since such structure isnoisy in operation and is subject to undue wear of the pistons andassociated parts. This apparently results from the fact that the trackis disposed in eccentric relation to the cylinder block, hence theangular velocities of the pistons with respect to the center of rotationof the track are not all the same. The pistons must therefore slipcircumterentially with respect to the ring.

While the hydraulic unit according to the invention is referred toherein as a pump, it will be recognized by those skilled in the art thatthe device may be used with equal facility as a motor. The term pump, asused herein, will therefore be understood as synonymous with the termmotor and, in the appended claims, pump and motor will be construed asmechanical equivalents.

An object of the invention resides in the provision of a pump in whichthe pistons coact directly with a rotating guide.

Another object of the invention is the provision of a pump in which thepiston guide is positively driven by the cylinder block.

Another object of the invention is to provide a positive displacementpump in which the pistons are rotated within the cylinders.

Another object of the invention is the provision of a pump in whichinertia forces are minimized.

A further object of the invention is a provision of a radial cylinderpositive displacement pump which is compact, light in weight, and smoothof operation.

Other objects and advantages more or less ancillary to the foregoing andthe manner in which all the various objects are realized will appear inthe following description, which, considered in connection with theaccompanying drawings, sets forth the preferred embodiment of theinvention.

For purposes of illustration, the invention is shown herein as embodiedin a pump of the type disclosed in my copending application, Serial No.637,699, for Hydraulic Fluid Mechanism, filed December 28, 1945,although it will be apparent that the invention may be embodied in pumpsor other mechanisms of a different design.

Referring to the drawings:

Fig. 1 is a vertical section taken through the axis of the pump on theplane indicated by the line l| in Fig. 2;

Fig. 2 is a vertical section taken on the plane indicated by the line2-2 in Fig. 1;

Fig. 3 is a horizontal section of the pump, taken on the plane indicatedby the line 33 in Fig. 2;

Fig. 4 is a sectional view of a fragmentary portion of the pump, thesection being taken on the plane indicated by the line 4-4 in Fig. 2;

Fig. 5 is an end elevational view of the pump rotor with the couplingring in place;

Fig. 6 is a side elevational view of the pump rotor with the couplingring in place;

Figs. '7, 8, and 9 are elevational views of the coupling ring;

Fig. 10 is an end view of the track ring;

Fig. 11 is an end view of the valve block; and

Fig. 12 is an elevational view of the valve plate.

The preferred embodiment of the pump embodies a casing 20 having a coverplate 2| secured thereon by bolts 23. A cylinder block 23 is mounted forrotation within the casing upon a hub 24 within a bushing a in the endwall of the casing and upon a thrust and Journal bearing 23 in a bore inthe cover plate II. The cylinder block is formed with a trunnion orshaft 2! disposed in axial alignment with the hub 24 and mounted forrotation within the Journal bearing II. A broached socket 28 in the endof the shaft 31 provides for the reception of a coupling member 21a bymeans of which the pump is driven. Suitable sealing means to preventleakage of fluid along the shaft 21. such. for example. as thosedisclosed in my above mentioned copending appllcation, may be mountedwithin the recess 29 in the cover plate I i.

The pump mechanism comprises a plurality of pistons ll mounted forreciprocation in radial cylinders 32 in the cylinder block 21 (Figs. 1and 2) The movement of the pistons within the cylinders is effected bythe engagement of the spherical outer ends so thereof with the innersurface of a ring or track 33 which is mounted in eccentric relation tothe axis of rotation of the cylinder block 23. The fluid flow to andfrom each cylinder is effected through an opening 33 (Figs. 1 and 2) ina cylindrical valve block 38 which is mounted in the center of thecylinder block it for rotation therewith. The openings 33 communicatewith elongated ports as (Figs. 3 and 11) formed in the face of the valveblock 38. The cooperating part of the valve: mechanism comprises a valveplate 40 (Figs. 3 and 12) provided with elongated arcuate openings IIand 2 disposed in radial alignment with the ports 38. The openings 4iand 42 constitute continuations of passages a and 42a (Fig. 3) in thecasing II, which communicate respectively with the intake opening ll andthe discharge opening 44 formed in a boss 45 of the casing 2|. Duringthe outward movement of each piston, the corresponding port as overliesthe opening ii in the valve plate 40, and during the discharge stroke ofeach piston, the port 39 will communicate with the discharge opening 42.

The valve plate In is restrained from rotation by dowel pins 43 (Fig. I)inserted in the valve plate and into the casing 20. In order to maintainthe valve block 38 in seated engagement with the valve plate 40, acompression spring 47 (Fig.

8) is mounted in a bore 48 in the valve block and an axially alignedopening 4! in the cylinder block. A fluid seal between the cylinderblock and the valve plate is effected through the provision of O-ringsor other sealing devices 50 and ll. As will be seen in Fig. 4, dowels 32inserted in openings in the cylinder block 23 and valve block Itconstrain these parts from rotation relative to each other.

As shown in Figs. 1 and 3, floating pistons 54 mounted in borescommunicating with the openings N in the valve block 33 provide, underthe action of the conflned fluid, a force against the surface I of thecylinder block 23 which maintains the valve block in intimate engagementwith the valve plate It. The pistons II are provided with a sealing ringit in a circumferential groove in the central portions of the bodythereof. A channel (Fig. 1) permits such fluid as may escape around thevalve block and floating pistons to be thrown outward centrifugally intothe casing.

The outer face of the cover plate II is preferably machined with a pilotbearing 88 to accommodate the alignment thereof with the prime ing thecoupling. Drainage may be effected by removal of the threaded plugs 60in the outer ends of the openings 58.

The structure so far disclosed corresponds to I that in theabove-mentioned copending application, and is substantially identicaltherewith except for the form of the pistons and the guide ring ortrack. In the prior application, a fixed guide ring is shown, and thepistons are provided with shoes which slide upon the inner surface ofthe ring. In the pump embodying the present invention, the guide ring 33(Figs. 1 and 2) is journaled for rotation in a bushing 63 mounted in thecasing 28 and is restrained against axial movement by a shoulder 64engaged with the bushing 63, and by a thrust bearing 65 mounted in thecover plate 2i. The ring is formed with an inwardly directed flange 66and a bead 61 on the opposed marginal edge thereof. The ring 33 ispositively driven by the rotor 23 through an Oldham type couplingillustrated generally in Fig. 6 and in further detail in Figs. 7, 8, and9. The flange 68 of the ring 33 (Fig. 10) is machined with diametricallyopposed slots 68 in the inner edge thereof which receive driving lugs 69formed in a coupling ring Ill disposed in contiguous relation with theflange. The slots 68 in the ring are formed to facilitate the smoothsliding engagement of the lugs therein. The face of the ring 10 oppositethe lugs 69 is formed with diametrically opposed sector projections 12,the inner vertical walls 13 of which are beveled for sliding engagementwith similar ledges It in a plate It mounted upon the inner face of thecylinder block 23 (Fig. 6). The undercut ledges 13 and the spacedrelation thereof form a dovetail connection by means of which the ring10 may slide radially relative to the plate 15. The plate 15 may befixed to the cylinder block 23 by countersunk flat-head machine screwsll (Figs. 5 and 6) or may be made integral therewith. The guide ways inthe cylinder block 23 and ring 33 are normal to each other, hence,during the eccentric movement of the block, the ring 33 may shiftradially relative thereto. With this construction the ring will attainthe same'velocity of rotation as the cylinder block throughout theoperative cycle of the pump. Since the ring is eccentric to the block,the engaging faces of the pistons will creep or slide circumferentlallyto a limited extent in relation to the ring. Under the influence of thecoupling, the sliding movement of the ring is uniform, hence there is noirregular movegagement with one or another of the pistons. ment of thering resulting from frictional engagement with one or another of thepistons.

The relative movement of the ring and pistons is utilized to effect arotary motion of the pistons within the cylinders during thereciprocation thereof. This is accomplished by forming the pistons withdomed outer ends and constructing the inner surface ,of the ring at aslight angle to the medial axis of the pistons. Since the cylinders areperpendicular to the axis of rotation of the block and since the innersurface of the guide ring is divergent thereto, say, an angle of twodegrees, thecontacting point of the piston will be engaged slightly toone side of the axis of the piston and as the pistons move back andforth circumferentially with respect to the ring. they will rotate orturn about their axis within the cylinders. This motion, combinedwiththe reciprocating motion of the pistons, results in a helical motion of.the pistons, which will affect an even distribution of wear upon theengaged walls of the cylinders and thus minimize the tendency of thepistons to score the cylinder walls.

An important advantage inherent in the use of the Oldham type couplingis in the reduction of vibration. Pumps and motors of the type disclosedherein are used at high and varying speeds and loads, and, particularlyin aircraft service, the weight must be minimized.

Vibration is usually eliminated by damping force or by employment of aresonating mass. It is apparentthat ahnost any mode of vibration,torsional, transverse, or longitudinal, of the cylinder block or casing,will result in relative movement of the parts of the coupling. Thissliding movement will be accompanied by friction tending to damp out thevibrations.

Although the foregoing description is necessarily of a detailedcharacter, in order that the invention may be completely set forth, itis to be understood that the specific terminology is not intended to berestrictive or confining, and that various rearrangements of parts andmodifications of detail may be resorted to without departing from thescope or spirit of the invention as herein claimed.

I claim:

1. A hydraulic device comprising a casing supporting a fixed valvemember at one end thereof, a cylinder block mounted for rotation in thecasing, the fixed valve member having a valve face symmetric about theaxis of rotation of the cylinder block, the cylinder block havingradially directed cylinder openings and an axially directed openingextending into the cylinder block from the fixed valve end thereof, amovable valve member positioned in the axially directed opening andhaving a valve face cooperating with the face of the fixed valve member,the movable valve member being constrained to rotate with the cylinderblock but free to move axially to engage the fixed valve member, thevalve members having cooperating ports and passageways for conductingfiuid to and from the cylinder openings as the cylinder block rotates,pistons in the cylinder openings having domed outer ends, an annularmember surrounding the cylinder block and mounted in the casing forrotation about an axis eccentric to the axis of the cylinder block, theinner surface of the annular member being slightly frustro-conical withrespect to the axis of the annular member and the domed heads of thepistons bearing against that surface, and a coupling device between thecylinder block and the ring for positively driving the ring with thecylinder block, whereby the slight component of axial thrust due to theengagement of the domed heads of the pistons with the inner surface ofthe annular member serves to minimize relatiw vibration between themovable valve member and the cylinder block and the fixed valve member.

2. A hydraulic device comprising a casing having a valve end and a driveend and supporting a fixed valve member at the valve end thereof,

a cylinder block mounted for rotation in the casing, the fixed valvemember having a valve face symmetric about the axis of rotation aboutthe cylinder block, the cylinder block having radially directed cylinderopenings and an axially directed opening extending into the valve blockfrom the fixed valve end thereof, a movable valve member positioned inthe directed opening and having a valve face cooperating with the faceof e fixed valve member, the movable valve member being constrained torotate with the cylinder block but free to move axially to engage thefixed valve member, the valve members having cooperating ports andpassageways for conducting fluid to and from the cylinder openings asthe cylinder block rotates, pistons in the cylinder openings havingdomed outer ends, a first annular member surrounding the cylinder blockmounted for rotation about an axis eccentric to the axis of rotation ofthe cylinder block, the inner surface of the annular member beingfrustro-conical with respect to the axis thereof, the outer ends of thepistons bearing against that surface, the inner radius of the annularmember being greater at the valve end thereof, and the member having aninwardly directed portion at the drive end thereof, an annular thrustbearing supported-by the housing and engaging the inwardly directedportion of the member for receiving axial thrust due to the engagementof the pistons with the conical surface, and a coupling device betweenthe cylinder block and the annular member for positively driving themember with the cylinder block, whereby the slight component of axialthrust due to the engagement of the domed heads of the pistons with theinner surface of the annular member serves to minimize relativevibration between the cylinder block and the fixed valve member.

3. A hydraulic device comprising a casing having a valve end and a driveend and supporting a fixed valve member at the valve end thereof, acylinder block mounted for rotation in the casing, the fixed valvemember having a valve face symmetric about the axis of rotation aboutthe cylinder block, the cylinder block having radially directed cylinderopenings and an axially directed opening extending into the valve blockfrom the fixed valve end thereof, a movable valve member positioned inthe directed opening and having a valve face cooperating with the faceof the fixed valve member, the movable valve member being constrained torotate with the cylinder block but free to move axially to engage thefixed valve member, the valve members having cooperating ports andpassageways for conducting fluid to and from the cylinder openings asthe cylinder block rotates, pistons in the cylinder openings havingdomed outer ends, a first annular member surrounding the cylinder blockmounted for rotation about an axis eccentric to the axis of rotation ofthe cylinder block, the inner surface oi the annular member beingfrustro-conical with respect to the xis thereof, the outer ends of thepistons bearing against that surface, the inner radius of the annularmember being greater at the valve end thereof, and the member having aninwardly directed portion at they drive end thereof, an annular thrustbearing supported by the housing and engaging the inwardly directedportion of the member for receiving axial thrust due to the engagementof the pistons with the conical surface, and a second annular memberdisposed within the first annular member and coupled to the cylinderblock for relative motion in a first radial direction and coupled to thefirst annular member for relative motion in a second radial directionnormal to the first.

4. A hydraulic device comprising a casing, a cylinder block mounted forrotation in the caling, the cylinder block having radially directedcylinder openings, valve means comprising a fixed valve member supportedat one end of the casing having a valve face in a plane normal to theaxis of rotation of the block and means associated with the blockdefining a valve face cooperating with the face of the fixed valvemember, the valve means having cooperating ports and passageways forconducting fluid to and from the cylinder openings as the cylinder blockrotates, pistons in the cylinder openings having domed outer ends, anannular member surrounding the cylinder block and mounted in the casingfor rotation about an axis eccentric to the axis of the cylinder block,the inner surface of the annular member being slightly frustro-conicalwith respect to the axis of the member and the domed heads of thepistons bearing against that surface, the valve end of the ring havingthe greater inner radius, and a coupling device between the cylinderblock and the annular member for positively driving the member with thecylinder block, whereby the slight component of axial thrust due to theen gagement of the domed heads of the pistons with the inner surface ofthe member serves to minimize relative vibration between the cylinderblock and the fixed valve member.

5. A hydraulic device comprising a casing, a cylinder block mounted forrotation in the casing, the cylinder block having radially directedcylinder openings, valve means comprising a fixed valve member supportedat one end of the casing having a valve face in a plane normal to theaxis of rotation of the block and means associated with the blockdefining a valve face cooperating with the face of the fixed valvemember, the valve means having cooperating ports and passageways forconducting fluid to and from the cylinder openings as the cylinder blockrotates, pistons in the cylinder openings having domed outer ends, anannular member surrounding the cylinder block and mounted in the casingfor rotation about an axis eccentric to the axis of the cylinder block,the inner surface of the annular member being slightly frustro-conicalwith respect to the axis of the member and the domed heads of thepistons bearing against that surface, the valve end of the member havingthe greater inner radius, and a ring surrounding said block and mountedon the block to slide in a single radial direction with respect thereto,the ring being within the annular member, axial projections from saidring engaging a bifurcated inwardly directed portion of the annularmember, the ring being thereby constrained to move in a radial directionnormal to the direction of motion of the ring with respect to thecylinder block.

6. A hydraulic device comprising a casing having a valve end and a driveend, a cylinder block mounted for rotation in the casing, the cylinderblock having radially directed cylinder openings, valve means comprisinga fixed means associated with the casing and rotatable means associatedwith the cylinder block, the valve means being rotationally symmetricabout the axis of rotation of the cylinder block and defining a valveface generally normal to the axis of rotation of the block, the valvemembers having cooperating ports and passageways for conducting fluid toand from the cylinder openings as the cylinder block rotates, pistons inthe cylinder openings having domed outer ends, a first annular membersurrounding the cylinder block mounted for rotation about an axiseccentric to the axis of rotation of the cylinder block, the innersurface of the annular member being frustro-conical with respect to theaxis thereof, the outer ends of the pistons bearing against thatsurface, the inner radius of the annular member being greater at thevalve end thereof, and the member having an inwardly directed portion atthe drive end thereof, an annular thrustbearing supported by the housingand engaging the inwardly directed portion of the member for receivingaxial thrust due to the engagement of the pistons with the concialsurface, and a coupling device between the cylinder block and theannular member for positively driving the member with the cylinderblock, whereby the slight component of axial thrust due to theengagement of the domed heads of the pistons with the inner surface ofthe annular member serves to minimize vibration of the cylinder block.

'7. A hydraulic device comprising a casing having a valve end and adrive end, a cylinder block mounted for rotation in the casing, thecylinder block having radially directed cylinder openings, valve meanscomprising a fixed means associated with the casing and rotatable meansassociated with the cylinder block, the valve means being rotationallysymmetric about the axis of rotation of the cylinder block and defininga valve face generally normal to the axis of rotation of the block, thevalve members having cooperating ports and passageways for conductingfiuid to and from the cylinder openings as the cylinder block rctates,pistons in the cylinder openings having domed outer ends, a firstannular member surrounding the cylinder block mounted for rotation aboutan axis eccentric to the axis of rotation of the cylinder block, theinner surface of the annular member being frustro-conical with respectto the axis thereof, the outer ends of the pistons bearing against thatsurface, the inner radius of the annular member being greater at thevalve end thereof, and the member having an inwardly directed portion atthe drive end thereof, an annular thrust bearing supported by thehousing and engaging the inwardly directed portion of the member forreceiving axial thrust due to the engagement of the pistons with theconical surface, and a second annular member disposed within the firstannular member and coupled to the cylinder block for relative motion ina first radial direction and coupled to the first annular member forrelative motion in a second radial direction normal to the first.

JOHN W. OVERBEKE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,006,880 Benedek July 2, 19352,035,647 Ferris Mar. 31, 1936 2,262,593 Thomas Nov. 11, 1941 2,273,468Ferris Feb, 17, 1942 2,406,138 Ferris et al. Aug. 20, 1946 2,454,418Zimmermann Nov. 23, 1948 2,457,101 Horton Dec. 21, 1948 FOREIGN PATENTSNumber Country Date 649,437 France 1928

